Table 3.
Pigs behavioral responses during the different phases of the open-field arena test according to their treatment.
| Behavior | Treatments | p-Value | ||
|---|---|---|---|---|
| CG | DDG | SDG | ||
| (n = 24) | (n = 20) | (n = 20) | ||
| Phase 1 | ||||
| Locomotion | 35.83 ± 3.20 | 39.45 ± 3.39 | 34.40 ± 3.39 | 0.571 1 |
| Low-pitched vocalization | 20.66 ± 3.78 | 29.40 ± 4.14 | 19.45 ± 4.14 | 0.183 1 |
| High-pitched vocalization | 0 (0–0) | 0 (0–0) | 0 (0–0) | 0.562 3 |
| Phase 2 | ||||
| Locomotion | 11.34 ± 1.80 | 9.00 ± 1.88 | 8.80 ± 1.88 | 0.567 1 |
| Low-pitched vocalization | 16.92 ± 2.74 | 14.05 ± 2.94 | 12.60 ± 2.94 | 0.561 1 |
| High-pitched vocalization | 0 (0–0.75) | 0 (0–3.5) | 0 (0–0) | 0.152 3 |
| Latency to approach area (s) | 42.66 ± 4.24 a | 19.18 ± 4.81 b | 18.89 ± 3.66 b | 0.001 2 |
| Latency to first contact (s) | 48.22 ± 3.83 a | 31.34 ± 5.30 b | 22.62 ± 3.98 b | 0.001 2 |
| Time looking at the stockperson (%) | 47.43 ± 6.47 a | 23.30 ± 6.80 b | 22.29 ± 6.80 b | 0.027 1a |
| Time in area (%) | 20.14 ± 6.49 a | 45.77 ± 7.11 b | 45.39 ± 7.11 b | 0.002 1a |
| Time of contact (%) | 8.28 ± 4.79 a | 27.12 ± 5.25 b | 25.60 ± 5.25 b | 0.003 1a |
| Physical contact (frequency) | 0.74 ± 0.35 a | 1.85 ± 0.36 b | 2.15 ± 0.36 b | 0.039 1 |
| Phase 3 | ||||
| Locomotion | 21.98 ± 2.33 p | 13.95 ± 2.40 q | 14.50 ± 2.40 q | 0.058 1 |
| Low-pitched vocalization | 29.71 ± 5.19 p | 14 ± 5.45 q | 15 ± 5.45 q | 0.100 1 |
| High-pitched vocalization | 0 (0–2.75) p | 0 (0–0) q | 0 (0–0) q | 0.080 3 |
| Latency to approach area (s) | 42.21 ± 8.49 a | 4.09 ± 1.47 b | 9.07 ± 3.53 b | <0.001 2 |
| Latency to first contact (s) | 47.11 ± 8.97 a | 5.47 ± 1.64 b | 10.02 ± 3.65 b | <0.001 2 |
| Time looking at the stockperson (%) | 13.30 (3.18–28.05) a | 1.60 (0–8.35) b | 1.04 (0–5.87) b | 0.001 3 |
| Time in area (%) | 45.93 ± 7.42 a | 84.19 ± 7.82 b | 77.11 ± 7.82 b | 0.008 1a |
| Time of contact (%) | 37.64 ± 8.35 a | 76.35 ± 8.68 b | 65.30 ± 8.68 b | 0.014 1a |
| Physical contact (frequency) | 3.96 ± 0.78 | 3.75 ± 0.80 | 3.99 ± 0.80 | 0.975 1 |
| Climb on the stockperson (frequency) | 1.10 ± 0.54 | 1.65 ± 0.56 | 0.84 ± 0.56 | 0.592 1 |
| Phase 4 | ||||
| Locomotion | 37.90 ± 2.53 a | 28.62 ± 2.69 b | 23.22 ± 2.69 b | 0.005 1 |
| Low-pitched vocalization | 33.50 ± 3.49 a | 17.10 ± 3.77 b | 12.70 ± 3.77 b | 0.003 1 |
| High-pitched vocalization | 2 (0–12.50) a | 0 (0–0) b | 0 (0–0) b | 0.007 3 |
| Accepted strokes (%) | 25.36 ± 5.92 a | 80.51 ± 6.24 b | 84.77 ± 6.35 b | <0.001 1a |
| Attempts until first accepted stroke | 5.50 (4–8.50) a | 1 (1–2) b | 1 (1–2) b | <0.001 3 |
Values within a row with different letters significantly differ (a,b: p < 0.05) or tend to differ (p,q: 0.05 < p < 0.1). CG = control group; DDG = demonstrator dominant group; SDG = subordinate demonstrator group. Phase 1 = Habituation to arena; Phase 2 = Standing stationary person; Phase 3 = Sitting stationary person; Phase 4 = Moving person. 1 mixed ANOVA model; 1a mixed ANOVA based on angular transformation (df = 2); 2 Kaplan–Meier analysis (df = 2); 3 Kruskal–Wallis test (df = 2). Data analyzed with ANOVA mixed models are expressed as estimated marginal means and standard error means (E.M.M. ± S.E.M.) of non-transformed data. Data analyzed with the Kaplan–Meier method are expressed as means and standard error (m ± S.E.) and data analyzed with Kruskal–Wallis test are expressed with medians and interquartile ranges (md (Q25–Q75)).